OK, just realized I was looking at pictures of the 169B+ on Asus' website. Maybe the 169C+ does have a USB-C port and not just a USB-C to USB 3 micro B cable.
I agree. A device like this should have two USB-C ports on it so one could be hooked to the power supply and the other to the laptop so they both could get power from an AC outlet instead of relying on battery power.